Sound producer



A. F. PETERSON k Nov. 6, 1928.

SOUND PRODUCER k Filed on. 4, 1927 .N n .w N R E T ..T EWA RP, `ww mmm D N A 435 atmospheric pressure. the other side of the piston8 1s closed by a i Patented Nev..6,192a. l

'UNITED sLrAjrEs ,PAT1-:Nr OFFICE..

ANDREW F. PETERSON, OF OAKLAND, CALIFORNIA lASSI-GN OR T THE WESTINGHOUSE AIR BRAKE COHPANAY., 0F WILMER-DING, PENNSYLVANIA, A CORPORATION OF rnNNsYLvNu.

l SOUND PRODUCER.

Application led October 4, 1927. Serial No. 223,922?.

This invention relates to sound producers, and more particularly to a sound producer of the type employing a flexible diaphragm whichvis caused to vibrate by the action of pulsating air pressure to which the diaphragm is subject.

e pressure of air supplied to the device may vary, and this will result in causing the volume of sound to vary, and the principal l0 object of mv invention is to provide a sound producer o the abovetype in which means are provided for maintainin the volume of sound constant regardlesso the degree of pressure of air supplied to the device. y

In the accompanying drawing", the single ligure is a sectional view of a sound vproduc- -ing device embodying my invention'.

As shown 'in the drawing, the device may comprise a casing 1 having a chamber 2 and 2 0 'a central tube 3 which extends outwardly to forni a horn. -Mounted to engage the annular inlet face 4 of the tube is a flexible diaphragm 5,` said diaphragm being secured in the casing by a cover or cap lmember 6.

According to my invention, the member 6 is provided witha centrally disposed cylinder 7, in which ismounted a piston 8. i

The piston 8 is provided with a stem 9, the end of which is secured to the diaphragm 5.

Y 3o The chamber 10 atone side of piston Sis with chamber 12 connected through port 11 y at one side of diaphragm 5, and chamber 12 is open to the atmosphere by wayl of port 13, so that chambers The chamber 14 at cover plate 15, Jandvopening to chamber 14 through said late is a pipe 16 whlch 1s connected to a' uid pressure supply pipe 17.

*40'v Said lsupply p'pe is connected to a plug 18V having screw-threaded engagement in the casing 1 and having a passage 19which connects pipe 17 with chamber 2. In operation, when fluid under .pressure is supplied through pipe 17 to chamber 2, the

increase 1n New: in said chamber operates to move the di agm 5 -out of engagement with the inlet felge 4 of the tube 3. Thejopening of communication from chamber 2 to the tube 3 permits a sudden'rushr of lfluid `from said chamber to the tube andthe rate of out` flow exceedin the rate o'f inflow through the passage l19, t e pressure in chambery 2 reduces and' the diaphragm 5 moves back to `pressures is substantially 10 and-12 are subject to 4 diaphragm -su engage the inlet face 4. The above cycle is then repeated and thereby the diaphragm is caused to vibrate. A

In this action, the the pressure of fluid supplied to pipe 17 and the outward movement of the diaphragm is thus opposed by a pressure which is always proportional to Vthe pressure of fluid Supplied to the device.

piston 8 is Subject to If the supply pressure is low, the pressure on piston 8 will be correspondingly low, so that less resistance is oiiered to the move-A ment of the diaphragm when ,the supply pressure is low. When the supply pressure is high the resistance to the movement of the diaphragm is likewise high. l

As a consequence, the effect .of supplying fluid under pressure to chamber 2 at varying counter @Heet of the pressure acting on piston 8, and therefore the intensit of the vibratory movement of the diaph consequently the volume of sound is maintained substantially constant, regardless of the pressure of fluid employed.`

l While one illustrative embodiment of the mvention has been described in detail, it is not myintention to limit its scope to that of the appended claims.

Having now described my invention, what Iclaimas new and desire to secure by Letters Patent, 'is T i l. AA sound roducer comprising a flexible diaphragm subject to. the pressure of fluid in av chamber and controlling an outlet openingv'fromA said chamber and operated by an increase in pressure in said chamber for connecting said chamberto saidl outlet opening and a piston 'subject to the] pressure of lui supplied to said chamber ment of said diaphragm.

2. A sound roducer comprising a. flexible ject to the pressure of `fluid 1n a chamber and controlling an outlet opening' through which uid is vented from said chamber and a phragm and subject to the pressure of `fluid supplied to said chamber ina direction to oppose-the lluid pressure acting onsaid dia-v pmgm- 3. A sound producer comprising a liexlble diaphragm su in a chamber and controlling an outlet open ragm and for opposing move-v ]ect to the pressure of fluidE neutralized by the f- 1 embodiment or otherwise than by the terms .100 piston carried by said diay ing through which fluid is vented from said chamber and a piston movable with said diaphragm and subject on one side to atmospheric pressure and on the opposite side to pressure of fluid supplied to said chamber.

4. A sound producer comprising a flexible diaphragm subject to the pressure of fluid in'a chamber and controlling an outletl opening through which Huid is vented from said chamber and a piston carried by said diaphragm and subject on one side to the pressure of Huid supplied to said chamber, the pressure on said piston opposing the movement of the diaphragm by the pressure acting in said chamber.

In testimony whereof I have hereunto set my hand.

ANDREW F. PETERSON. 

